Isaiah 59:2 versus "Original Sin"

Isaiah 59:2 reads "But your iniquities have separated between you and your God, and your sins have hid his face from you, that he will not hear."The Israelites’ sins (not Adam’s sin) separated them spiritually from God. The true Calvinist would have to believe Adam's sin separated the Isarelites from God.Before the Israelites’ sin, they were not separated from God. This contradicts the Calvinists' position that they would have already been separated by the “one sin of Adam.”